With the rapid development of semiconductor manufacturing technology, semiconductor devices are developed towards a direction of having a higher component density and a higher integration degree. As the most fundamental semiconductor devices, transistors have been widely used. With the improvement of the component density and the integration degree, the gate size of planar transistors also becomes smaller and smaller, the ability of traditional planar transistors in controlling the channel current is weakened, resulting in the short channel effect (SCE) and causing leakage current. As such, the electrical performance of the semiconductor devices may be degraded.
According to existing technology, in order to overcome the SCE in transistors and suppress the leakage current, a fin field-effect transistor (Fin-FET) has been adopted. A Fin-FET is a common multi-gate device, which includes a fin structure formed on the surface of a semiconductor substrate, and a dielectric layer formed on the semiconductor substrate. With a top surface lower than the top surface of the fin structure, the dielectric layer covers a portion of the sidewall surfaces of the fin structure. The Fin-FET also includes a gate structure formed on the surface of the dielectric layer and a portion of the top and sidewall surfaces of the fin structure, and a source region and a drain region formed in the fin structure on the two sides of the gate structure, respectively.
According to existing technology, a substitution material is usually used to form the fin structure in the Fin-FET to improve the mobility of the carriers in the channel and the drive current of the transistor, and thus improve the performance of the semiconductor structure.
However, for semiconductor structures having a fin structure formed using a substitution material according to existing technology, the self-heating issue may be severe. Therefore, the performance of the formed semiconductor structures may be degraded. The disclosed semiconductor structures and fabrication methods thereof are directed to solve one or more problems set forth above and other problems in the art.